School Start Times: an Opportunity to Improve our Kids Health and Performance

Many schools currently have start times aligned with adults circadian biology rather than that of kids, particularly teenagers. Our local school district, Oak Harbor, WA (a high performing district – they do great work) is one that has early start times for teenagers. This discussion is particularly relevant for me as my daughter (now a teenager, yikes) has started middle school and arrives there before 7:30 am every day.

To start the analysis, please listen to this ~5min discussion from recent Bulletproof Radio episode¹:

The highlights from this clip:

• Satchin Panda is one of the leading researches on circadian rhythm. He published a book last year, and I shared some of the highlights I saved on my kindle here.
• Seattle school changed from 7:30 am to 8:30 am despite resistance from teachers/parents (they normally get up earlier).
• 200 students from 2 different schools for 75 days and tracked grades before and after the change. The students gained 34 minutes, which is equivalent to what was achieved in the 1950s.
• Grades improved by nearly 5%.
• Less traffic accidents (kids driving aren’t as tired).
• The video below is the study’s co-author from a Eureka Alert article summarizing the study.²

Read on to learn more and let’s work together to spread the word with the school district for a later start time!

Sleep has been a focus of mine over the last few years, but that was taken to a new level over the last year when I started using an Oura ring. This ring tracks many metrics, including deep sleep and REM. Along with heart rate, heart rate variability, and body temperature, it is easy to see a cause and effect in real time with actions taken on a daily basis and how they impact sleep and performance. If I am thrown off my circadian rhythm, by travel, social events, etc, my sleep metrics and the resultant ability to perform and simply feel good is diminished. The good news is my schedule is tailored to my natural circadian rhythm, which is on the earlier side; up around 5-6am in bed between 9-10pm. This is not the same for my 13 year old…

As kids age their circadian rhythm goes from seemingly non-existant as infants, to early risers, to late risers (and then typically back to earlier in adulthood):

Adolescent teenagers, however, have a different circadian rhythm from their young siblings. During puberty, the timing of the suprachiasmatic nucleus is shifted progressively forward: a change that is common across all adolescents, irrespective of culture or geography. So far forward, in fact, it passes even the timing of their adult parents.


As a consequence, the sixteen-year-old will usually have no interest in sleeping at nine p.m. Instead, peak wakefulness is usually still in play at that hour. By the time the parents are getting tired, as their circadian rhythms take a downturn and melatonin release instructs sleep—perhaps around ten or eleven p.m., their teenager can still be wide awake. A few more hours must pass before the circadian rhythm of a teenage brain begins to shut down alertness and allow for easy, sound sleep to begin.

Matthew Walker, Why We Sleep: Unlocking the Power of Sleep and Dreams, pg. 92-93 (here is a short summary of my kindle notes on his book)

The problem is, at least in most schools is the start times are opposite, the little kids start later and the older kids earlier. Here is a quick summary of our district, the high school time shown is the 0 period (1st is 7:55am)

Below are a few excerpts from various books I have read that address this issue:

• “Adolescents who get less sleep than they need are at higher risk for depression, suicide, substance abuse and car crashes,” according to the journal Pediatrics. “Evidence also links short sleep duration with obesity and a weakened immune system.”2 While younger students score higher on standardized tests scheduled in the morning, teenagers do better later in the day. Early start times correlate strongly with worse grades and lower test scores, especially in math and language.3 ³
• The evidence of harm is so massive that in 2014 the American Academy of Pediatrics (AAP) issued a policy statement calling for middle schools and high schools to begin no earlier than 8:30 a.m.5 A few years later, the CDC added its voice, concluding that “delaying school start times has the potential for the greatest population impact” in boosting teenage learning and well-being.⁴
• A lot of scientific evidence supports the idea that high schools should start later in the morning.25,26,27 Delayed start times would positively affect students’ circadian code and would improve their alignment of all three factors: light, sleep, and food.⁵
• adolescents are most sensitive to evening light, which delays their clock and bedtime. Their circadian clock does not wake them up early, yet schools are all scheduled to start early, sometimes before sunrise.⁶
• In the year before this time change, the average verbal SAT scores of the top-performing students was a very respectable 605. The following year, after switching to an 8:30 a.m. start time, that score rose to an average 761 for the same top-tier bracket of students. Math SAT scores also improved, increasing from an average of 683 in the year prior to the time change, to 739 in the year after. Add this all up, and you see that investing in delaying school start times—allowing students more sleep and better alignment with their unchangeable biological rhythms—returned a net SAT profit of 212 points. That improvement will change which tier of university those teenagers go to, potentially altering their subsequent life trajectories as a consequence.⁷

All of this information really crystalized for me by experience this year; data and stats are interesting, but seeing it cause difficulties for my daughter first-hand takes it to the next level. Dragging her out of bed in the pitch black isn’t good for her, or the parent charged with doing so (she can be less than pleasant, understandably). We are fortunate she doesn’t have to ride the bus and can carpool with a friend, but still, 6:15 am for a 13-year-old is problematic. Teens most productive time is in the evening, but with the early wake up there is a lot of pressure to get to bed early. This further limits productive study time.

I have had good conversations with School District employees. There is a measure of receptivity, but we will need a group effort to coordinate. Please use this form below to join a team interested in aligning school start times with their biology to achieve better health and performance.

1. https://blog.bulletproof.com/satchin-panda-560/
2. https://www.eurekalert.org/pub_releases/2018-12/aaft-dhs121018.php
3. Daniel H. Pink, When: The Scientific Secrets of Perfect Timing, loc. 1169
4. Daniel H. Pink, When: The Scientific Secrets of Perfect Timing, loc. 1176
5. Satchin Panda, The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight, loc. 2232
6. Satchin Panda, The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight, loc. 2236
7. Walker, Matthew. Why We Sleep: Unlocking the Power of Sleep and Dreams (pp. 311-312). Scribner. Kindle Edition.